Design And Research Of The PID Temperature Controling System Based On Air-source Heat Pump Water Supply Unit

Air-source heat pump water supply system has the advantage of safety,convenience,high efficiency and energy saving.On the one hand,it has a very low cost of use.On the other hand,it also meets the increasingly stringent requirements for electricity safety and energy saving and environmental protection.At home and abroad,there is a wide space for its development.But because the outlet temperature of the air-source heated pump water supply system is affected by the valve motor adjustment into water flow control,environmental adaptability and water temperature and other conditions.It has a large time lag and non-linearity.And in the actual practice,the water temperature is not easy to reach the requirement that the temperature water should come out in a rapid and constant way.Our research is based on the traditional PID algorithm used in the heated pump temperature control system.And the feed-forward control,the temperature sloped control and the valve tracking control are also introduced.An optimization PID temperature control scheme with parameter self-adjustment and fast prediction is proposed.Through our further research on the temperature control process and temperature control requirements of the air-source heated pump water supply system,a constant temperature control system built up by two pieces of AT89S52 single-chip microcomputers is designed,based on the analysis and treatment of the feedback signal of the temperature sensor and the slope tracking control.The opening and closing degree of the motor is adjusted to control the flow of the water,and then the water temperature is kept constantly at the target temperature.The temperature control scheme is applied to the air source heated pump unit,and solves the problems such as the overshoot of the valve in the past,the fluctuation of the water temperature and so on.The air-source heated pump water supply system reaches the requirement of quickness and stability,no fluctuation,low overshoot constant temperature water ultimately.Through the comparison of the actual application effect between the optimized PID and the traditional PID in the constant temperature control system,the system has the advantage of fast response,high stability,high temperature regulation precision and intelligent energy saving according to the environment temperature.Now the constant temperature control system has been put into practice.At the end of our paper,the control scheme of airsource heated pump water supply system is summarized and prospected.